Carriage assembly

Abstract

A carriage assembly for use with an optical recording disc for optical recording and reproduction relative to the disc comprises a frame, an optical lens for projecting and receiving a light beam for the optical recording and reproduction, a carriage movably supported in the frame for supporting the optical lens relative to the disc, a vertical guide arrangement for permitting a movement of the optical lens relative to the carriage in a vertical direction relative the disc surface, a vertical drive arrangement for driving the optical lens in the vertical direction relative to the carriage, a radial guide arrangement for permitting said carriage to move in a radial direction of said optical disc, and a radial drive arrangement for driving the carriage in the radial direction of the disc. The vertical drive arrangement includes a permanent magnet and an electromagnetic coil electromagnetically coupled with the permanent magnet, one of the permanent magnet and the electromagnetic coil being mounted to the optical lens and the other of them being mounted to the frame, whereby the carriage assembly is reduced in both weight and physical dimensions.

What is claimed is: 
     
       1. A carriage assembly for use with an optical recording disc, said carriage assembly comprising: a box-shaped frame having walls of magnetic material surrounding an interior, said walls including a top wall having a narrow elongated slot located intermediate side walls of said frame, said top walls on opposite sides of said slot, said side walls and a bottom wall providing a closed magnetic circuit including the slot;   an optical lens which projects and receives a light beam;   a carriage movably supported in the interior of said frame and carrying said optical lens for movement parallel to the slot in a radial direction relative to an optical recording disc;   vertical guide means including a lens support extending into the slot for guiding movement of said optical lens relative to said carriage in a vertical direction relative to a disc surface;   vertical drive means for driving said lens support relative to said carriage in the vertical direction;   radial guide means for guiding movement of said carriage in a radial direction relative to the optical disc; and   radial drive means for driving said carriage relative to said frame in the radial direction, said radial drive means including a magnet and a coil electromagnetically coupled by flux in a closed magnetic circuit formed by walls of said frame surrounding said radial drive magnet and coil;   said vertical drive means including a permanent magnet and an electromagnetic coil electromagnetically coupled with said permanent magnet by flux of the closed magnetic circuit, and one of said permanent magnet and said electromagnetic coil being mounted to said lens support in the slot and the other of them being mounted to said frame in the slot.   
     
     
       2. A carriage assembly as claimed in claim 1 wherein said vertical guide means is a support member mounted to said carriage for resiliently supporting said optical lens. 
     
     
       3. A carriage assembly as claimed in claim 1 wherein a wall of said frame facing the disc surface has a slot elongated in the radial direction of the disc. 
     
     
       4. A carriage assembly as claimed in claim 3 wherein siad vertical drive means includes an electromagnetic coil mounted to said frame along the elongated slot and a permanent magnet mounted to said optical lens. 
     
     
       5. A carriage assembly as claimed in claim 3 wherein said vertical drive means includes a permanent magnet mounted to said frame along the elongated slot and an electromagnetic coil mounted to said optical lens. 
     
     
       6. A carriage assembly as claimed in claim 3 wherein said vertical drive means includes a permanent magnet mounted to said optical lens and a plurality of electromagnetic coils mounted to said frame along the elongated slot. 
     
     
       7. A carriage assembly as claimed in claim 3 wherein said vertical drive means includes an electromagnetic coil mounted to said optical lens and a plurality of permanent magnets mounted to said frame along the elongated slot. 
     
     
       8. A carriage assembly as claimed in claim 3 wherein said vertical drive means includes an electromagnetic coil mounted to said frame along the elongated slot and a plurality of permanent magnets mounted to said optical lens. 
     
     
       9. A carriage assembly as claimed in claim 3 wherein said vertical drive means includes a permanent magnet mounted to said frame along the elongated slot and a plurality of electromagnetic coils mounted to said optical lens. 
     
     
       10. A carriage assembly for use with an optical disc, said carriage assembly comprising: (a) a frame for mounting in proximity to a surface of an optical disc, said frame being box-shaped and having walls of magnetic material surrounding an interior, said walls including a top wall facing the disc surface and having a narrow slot elongated in the radial direction of the disc and located intermediate side walls of said frame, said top wall on opposite sides of the slot, said side walls and a bottom wall providing a closed magnetic circuit including the slot;   (b) a carriage movably supported in the interior of said frame for movement along a first path in a radial direction of the disc parallel to the slot;   (c) a voice coil-type linear motor having radial drive components comprising a magnet and an electromagnetic coil; (i) one of said radial drive components being mounted on said frame in the interior thereof in proximity to the first path, and   (ii) the other of said radial drive components being mounted on said carriage such that said walls of said frame surround said radial drive components and provide a magnetic yoke for flux coupling said radial drive components;     (d) a lens support movably supported on said carriage by a plurality of gimbal springs for movement in a direction perpendicular to the disc surface and disposed on said carriage so as to extend into the slot and carried by movement of said carriage along a second path parallel to and in alignment with the slot;   (e) a lens support drive magnet;   (f) a lens support drive coil, one of said lens support drive magnet and said lens support drive coil being mounted on said frame in the slot and the other being mountd on said lens support in the slot so as to be electromagnetically coupled by flux in the closed magnetic circuit including the slot to drive the lens support along the second path; and   (g) an optical lens mounted on said lens support which projects and receives a light beam from the surface of the disc.   
     
     
       11. A carriage assembly for use with an optical recording disc, said carriage assembly comprising: a frame;   an optical lens which projects and receives a light beam for optical recording and reproduction;   a carriage movably supported in said frame and a carrying said optical lens for movement in a radial direction relative to an optical recording disc;   vertical guide means including a lens support for guiding movement of said optical lens relative to said carriage in a vertical direction relative to a disc surface;   a vertical drive means for driving said lens support relative to said carriage in the vertical direction;   radial guide means for guiding movement of said carriage in a radial direction relative to the optical disc; and   radial drive means for driving said carriage relative to said frame in the radial direction;   said vertical drive means including a permanent magnet and an electromagnetic coil electromagnetically coupled with said permanent magnet, and one of said permanent magnet and said electromagnetic coil being mounted to said lens support and the other of them being mounted to said frame wherein said radial guide means includes a linear bearing mounted to said carriage and a center pole piece mounted to said frame, said center pole piece serving as a guide rail.